alright, just tested the wal-mart external power method, i got about 35 hrs w/ the walmart car adapter and a 12v 7.2amp battery!
seems to be about 10 hrs less than alex's tests w/ the "real" creative car adapter, but thats fine for me, it actually may have lasted less, because i had my internals in, D'oh!!!
either way, its a jb3 HD worth, which is worth it to me for sure!
im gonna do more tests because im anal and i wanna seee if a full charge w/ the batteryminder may do any change also!!